Nozzle diaphragm



J. H. DORAN 2,196,062

NO Z ZLE DIAPHRAGM April 2, 1940.

Filed June 5, 1938 nvento HB5 Attorneg J Y1 H.DO" n Patented Apr. 2, 1940 NozzLE DIAPHRAGMv John H. Doran, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application June 3, 1938, Serial No. 211,590

Claims.

The present invention relates to nozzle diaphragms such as are used in elasticfluid turbines for conducting elastic fluid to bucket wheels. More particularly, the invention relates to the 5 type of nozzle diaphragms which includes a nozzle structure having inner and outer bands and a plurality of spaced nozzle blades secured to the bands and forming nozzle passages for directing the ow of elastic fluid to a bucket wheel. The inner band is usually united with a disk while the outer band is united with a solid ring.

An arrangement of this kind is disclosed in the patent to H. A. Lacey, No. 1,932,278, issued Oct. 24, 1933, and assigned to the same assignee as the present application. The outlet edges of the nozzle blades are thin and when exposed to the high pressuresv and temperatures in modern elasticfluid turbines they are subjected to excessive strains and stresses which may lead to damage of the thin outlet edges.

The object of my invention is to provide an improved nozzle diaphragm whereby the thin outlet edges of the nozzle blades are relieved from excessive strain. This is accomplished in accordance with my invention by a nozzle diaphragm arrangement permitting expansion and contraction of the thin outlet portions of the 'nozzle blades without setting up therein excessive stresses. To this end the ends of the thin outlet portions of the nozzle blades are secured to a resilient band or a resilient portion of a band.

For a better understanding of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing in which Fig. 1 is a sectional view through a turbine nozzle diaphragm and bucket wheel arrangement embodying my invention, Fig. 2 is a view'along line 2-2 of Fig. 1

50 a recess I4 of a disk I5 and united with the latter by a weld I6. The outer band I3 is seated in a recess I'I of a solid outer ring I8 and united therewith by a weld I9. The nozzle diaphragm serves to conduct elastic fluid to a ring of buckets 55 2| on a bucket wheel 20 arranged in cooperative relation with the diaphragm. Buckets 2I' have their inner ends suitably fastened to a disk or wheel 22 and outer ends connected by a shroud band 23. f

In order to prevent excessive strains and stresses from being set up in the thinV outlet portions II of the nozzle blades I0, the end portions of the inner and outer bands I2 and I3 near said thin outlet portions Il are made resilient. In the present example the end portions 24 and 25 of the inner and outer bands respectively are reduced in thickness and free to expand and contract in radial direction. In other words, these thin portions 24 and 25 are not secured to the solid disk I5 and the solid ring I8 respectively.

A simple method of producing such structure is rst to form a structure of the conventional type with inner and outer bands I2 and I3 having outer cylindrical surfaces and completely uniting these cylindrical surfaces with the disk and outer ring respectively, as shown in theA aforementioned patent. Thereafter the thin free portions 24 and 25 of the inner and outer band respectively may be produced by machining grooves 25 and 2l into the adjacent portions of the weld I5 and the inner band and the weld I9 and the outer band respectively. After manufacture the band I3 together with the weld I9 and the outer ring I8 form a unitary structure secured to the outer ends of the nozzle blades It. This unitary structure has a groove 2l to dene a flexible or resilient member 25 connected to the thin outlet portions Il of the blades I0. Likewise the disk I5 with the band I2 and the weld I6 may be considered as a unitary structure fastened or united with the inner ends of the blades I0 and having a flexible member or lip 24 united with the vthin outlet portions II of the blades to avoid the setting up of excessivestresses in said thin outlet portions during operation. The lips or thin portions 24, 25 are free to expand relative to the solid structures.

Having described the method of operation of my invention together with the apparatus which I now consider to represent the bestemboclirne'nt thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

the nozzle structure and a Weld uniting the band With the solid member, the band portion near the thin outlet edges of the blades being resilient and free to expand relative to the solid member.

2. Nozzle diaphragm comprising a plurality of spaced nozzle blades having thin outlet edges, inner and outer bands secured to the ends of the blades, said bands having portions reduced in thickness near the outlet edges of the blades, a disk forming a seat for the inner band, a Weld uniting the inner band to the disk, a solid ring forming a seat for the outer band, and a Weld uniting the outer band with the ring, the reduced portions of the bands being free to expand relative to the disk and the ring.

3. Nozzle structure for diaphragms comprising a band having an edge portion reduced in thickness to render such edge portion resilient, and a plurality of spaced nozzle blades With thin outlet portions having ends united with the band, the thin outlet portions of the blades being united with the reduced edge portion of the band to prevent breaking of the thin outlet portions of the blades when subject to high temperature changes.

4. Nozzle diaphragm comprising a plurality of spaced nozzle blades having thin outlet portions, and a unitary structure united with the ends of the blades, said unitary structure having a recess near the thin outlet portions to form a resilient; member connecting the ends of the thin outlet portions to the unitary structure to prevent breaking of the thin outlet portions of the blades when subject to high temperature changes.

5. Nozzle diaphragm including a plurality of nozzle blades having thin outlet portions, and a rigid unitary structure having a resilient portion and connected to the ends of the blades with the resilient portion connected to the thin outlet portions of the blades to eliminate excessive strains and stresses in said thin outlet portions tosprevent breaking of the thin outlet portions of the blades when subject to high temperature changes.

JOHN H. DORAN. 

